Spray-dried, non-clotting, granulated soap product and method of producing the same



Irving Reich, West New York, and William A. Kelly, Teane'ck, NJ., assignors to Lever Brothers Company, New York, N.Y., a corporation of Maine N Drawing. Filed Dec. 20, 1955, Ser. No. 554,143

, 11 Claims. (21. 252-109 The present invention relates to a soap product and *to a method of producing the same, and more particularly to a spray-dried, non-clotting, granulated soap product and to a method of producing the same.

Granulated soap products are soaps which have been prepared for household use by slurrying the soaps with water, spraying the slurry, and drying the droplets in heated air. They consist of tiny granules, more or less irregular in shape. Usually they include a few percent of inorganic and alkaline substances, such as sodium silicate and tetrasodium pyrophosphate, in addition to the soap. Granulated soap products of this type are widely used for household washing.- One of the main advantages of this form of soap product is the relatively short time required in which water solutions or dispersions of soluble soaps may be obtained as compared with the time required to do so when using bars or sliced or chipped forms.

Conventional granulated soap products, however, show 1 a tendency to lump together when thrown into hot water. Apparently the granules float on the surface, become pasty and sticky as the hot water wets and partially melts them, and then stick together in a coherent pasty mass or clot. These clots may vary in size from that of a grain of 'rice to that of a large thumb. Large clots may consist of a pasty surface layer with dry, unwet powder inside. Since the clots dissolve very slowly, the formation of clots delays proper sudsing and cleansing action. In addition, the clots are also unattractive in appearance.

Furthermore, clotted soap products adhere to fabrics or surfaces being washed, in some instances leaving the surfaces smeared or blotched even after the washing and rinsing procedures have been completed.

The tendency of granulated soap products to form clots 5 may be reduced if the soap is first dispersed in cold water and this dispersion is then poured into hot water. This, however, is 'an inconvenient extra operation. It is not easily accomplished in all types of mechanical washers.

Furthermore, when it can. be done it may also result in reducing the temperature of the hot water below that required for proper washing action.

The tendency of granulated soap products to clot may also be reduced by forming the granulate particles as irregular or scraggly particles rather than as puffed or hollow particles. An irregular or scraggly particle when poured into water will met. more quickly than a rounded or rounded and puffed particle possibly due to the larger area exposed to the water. Quick wetting increases the solubility rate and places a water film between the individual particles, thereby tending to prevent them from sticking together.

' Granulated soap products of the type discussed above .are ordinarily made from tallow and otheranimal fats.

Tallow soap consists mainly of the mixture of the alkali" metal salts of stearic, palmitic, and oleic acid. 'It is common, however, to include a limited proportion, up to 'fabout 20%, of cocon ut oil soap. This consists mainly ofhthe m ixture of the alkali metal salts of lauric and myristic acid. It is known that the presence of sufliy 2,940,935 Patented June. 14,1960

ice v cient coconut oil soap reduces the tendency of the granulated soap productsto clot, because coconut oil soap due to its hardness dissolves rather than melting and gumrning before solubilizing and because it is one of the most'soluble of all soaps. However, coconut oil soap is considerably more'expensive than tallow soap. In addition, to reduce clotting significantly, over about 40% of coconut oil soap is required. This is undesirable in view of the high cost. Furthermore, it is known that at the high temperatures often used in washing fabrics, coconut oil soap isa poorer soap than is tallow soap, so that the use of this large proportion of coconut oil soap will impair detergency.

U.S. PatentNo. 2,388,632 to Byerly describes a method of reducing clotting by spray-drying the coconut oil soap and the tallow soap separately, and then mixing the two dried soaps mechanically. This permits some reduction in the total amount of coconut oil soap required to reduce clotting. However, an undesirably high proportion of coconut oil soap is still required. Also the requirements of spray-drying the two soaps separately and mechanically mixing the two after drying makes the process undesirably complicated and increase the cost of manufacturing operations. It is well known that a mixture of two different powders will tend to stratify in a container, especially when continually disturbed, as during freight transportation. For this reason, a mechanical mixture of this type is less desirable thanfa homogeneoiis product, wherein all grains have the same composition. v I

In an attempt to solve this problem of clotting the following test procedureiwas devised and employed in the examples set'forth herein. The results obtainedby this test procedure had correlated well with large scale test runs in washtubs. The procedure consisted of running 800 cc. of tapwater at: 125 F. into a 1000' cc. beaker. Ten grams of the granulated soap product was poured in a heap on the surface of the water. Stirring with a steel microspatula was begun immediately, using back and forth strokes the full width of the beaker, at the rate of strokes per minute. The clotting was graded after 30 seconds and again after 60 seconds of stirring according to the following system:

Grade No. Degree of Clotting Soap completely dissolved.

A few specks floating.

A number of clots of the size of rice grains.

Many clots, some as large as peas.

Nearly all the soap still floating as large clumps.

The clotting score is the total of the 30 and 60 second grades. Experience has shown that for practical use a soap product which scores 6 or more is bad, 5 is poor, 4 is fair, 3 is good, and 2 or less is excellent. Intermediate clotting scores are indicated by decimals. A soap product which has a clotting score of-6 or more, when thrown vonto the surface of .waterin a dishpan or washing machine, will form large clots which may not dissolve for 30 minutes. One which hasa clotting score of 2 or less will dissolve in a minute or two on gentle stirring. A granulated soap product having a clotting score of 3 or less is quite satisfactory and accordingly is non-clotting.

heated r0200" F; at'a' ressure of 80 p.s.i.g. and then spray-dried in a conventional spray-drying tower having I an entering air temperature of 200 F.

.Componeuts Percent by Weight Sodium Soap (92.5% Sodium Tallow Soapand 7.5% Sodium Coconut Oil Soap) V 7 7 100.

An: aqueous slurry of a soap product having the following composition by weight on an anhydrous basis was heated to 200 F. at a pressure of 80 p.s.i.g. and then spray-dried in a conventional spray-drying tower having an entering air temperature of 200' F.

Components Percent by Weight Sodium Soap (92.5% Sodium Tallow Soap and7 Sodium Coconut Oil Soap) i 90.0 Sodium Xylene Sulfonatc I 10.0

I T0 '7 lil -Q The spray-dried granulated soap product consisted of mixed pufied and scraggly particles and had a clotting score of 316.

Theaddition of an alkali metal carbonate to the soap also did not produce a spray-dried granulated soap prod- .uct' having a satisfactory clotting score as illustrated by theexample below.

5 i Example 3 An aqueous of asoap product having the following composition by weight'on an anhydrous basis was heated to 200 F. at a pressure of .80 p.s.i.g. and then spray-dried in a conventional spray-drying tower having an entering air temperature of 20 0 F.

Gomponents Percent by Weight Sodium Soap (92.5% Sodium Tallow Soap and 7.5% Sodium Coconut Oil Soap) I 94. 0 Sodium Carbonate 6. 0

Total 100. o

The spray-dried granulated soap product consisted of mostly scraggly particles and some puffed particles and had a clotting score of 4.6.

The addition of an alkali metal silicate to the soap likewise did not produce a spray-dried granulated soap product having a satisfactory clotting score as shown by the example set forth below;

Example .4

A aqueous slurry of a soap product having the following composition by weight on an anhydrous basis was heated to 200 F. at a pressure of 80 p.s.i.g. and then spray-dried in a conventional spray-drying tower having an entering air temperature of 200 F.

"2,940,935 a V a 4 I The spray-dried granulated soap product consisted of mixed puffed and scraggly particles and had a clotting score of 6.0.

In accordance with the present invention it was found that the tendency of granulated soaps to clot'can be re-- duced greatly to a satisfactory clotting score by the incorporation of a limited amount of an alkali metal xylenesulfonate and either an 'alkali metal silicate or an alkali metal carbonate in the soap slurry before spray drying.

Accordingly, the present invention provides a spraydried, non'clotting, granulated soap product consisting essentially of either an alkali metal silicate or an alkali metal carbonate, an alkali metal xylene sulfonate, an alkali metal coconut oil soap, and an alkali metal tallow soap. The invention also provides methods of preparing this product comprising heating an aqueous slurry of the product at atmospheric pressure and then spray-drying the slurry at a higher pressure or heating an aqueous slurry of the product ata pressure above atmospheric pressure and then spray-drying the slurry.

The alkali'metal silicate or alkali "metal carbonate is present in the soap product in an amount in the range from about 6% to about,18% by weight on an anhydrous basis. ployed include sodium silicate and vpotassium silicate. The preferred silicate is sodium, silicate. .Approximately 6% ofsodium silicate is commonly used in commercial granulated soaps to help improve detergency .and'to help in minimizing corrosion of'metals in the washing machine. Typical alkali metal carbonates which may be utilized include, for example, sodium carbonate and potassium carbonate, sodium carbonate being preferred.

Thealkali metal xylene sul-fonate may be, for example,

7 sodium xylene sulfonate or potassium xylene sulfonate.

At least about 2% by weight on an anhydrousfbasis of the alkali metal xylene sulfonate is present in the sprayrdried, non-clotting; granulated soap product. The upper limit of alkali metal Xylene sulfonate is not critical, but more than is necessary to achieve the desired non-clotting effect is normally not employed. The maximum suggested amount is about 18% by weight on an anhydrous basis. When the alkali metal xylenesulfonate content is about 6% or above, the granulated soap particles may exist either as scnaggly, irregular particles or as rounded or rounded and pufied particles. Howeyer when the alkali metal xylene sulfonate content is less than 6%, it is preferred t a he anul tsrlss rtis s x sta sc assl irregular particles rather than as puffed particles in order to insure maximumnonrelotting of the particles.

kali metal x n .su i on a e ens v s st n s ll known i th h al ind tr w p duce no undesirable eflcct on the appearance or use properties of the granulated soap product, It was found that the incorporation of an alkali metal xylfiiie sulfo nate increases therate at which individual granulesdissolvc. This is desirable when soap is to be dissolved in lukeflvarm or cool water.

The mixture of alkali metal coconut oil soap and alkali metal tallow soap amounts to'from about 6.4% to about 92% by weighton anhydrous basis. Of this amount from about 1% to about 20%, and preferably about 7%, is'alkali metal coconut oil soap and from about 99% to b u 80% 'a s c y. and P ferab y b u 3%. i alkali metal tallow soap, both soaps being expressed The alkali metal coconut oil soap manag r the alkali metalsalts of the mixture of fatty acids present vvComponents 7 Percent by l Weight Sodium Soap (92.5% SodlumTallowSoap and 7.5% Sodium Coconut Oil Soap) 93.3 Sodium Silicate V Y 6.7 :T otel. i I 100.0

Qq u Q h h e fatty id ar ma l la d and ni ac is s- Coc nu o how ve al o s ntam ss xl a id. qa is ac d p lni i a id c i ak n; ansl sl l a id. The alkal m t sa t ,Q these a d ma b by passe pr m ril of pu s g n e dlq s Typical alkali metal silicates which may be em:

v l 1 l but also includes a minor proportion of myristic acid. The alkali metal salts of these acids may be, by way of example, the sodium or potassium salts.

It will be appreciated that the spray-dried, non-clot- The spray-dried granulated soap product consisted of mixed puffed and scraggly particles and had a clot-ting score of 2.75.

Example 7 22 gianulated 9 PmduFt may contain 3.8mm amount An aqueous slurry of a soap product having the folmoisture therein depending upon the desired degree of 1 b h .vanh d b d m i Mi 0 f m redi I owing composition y weig t on an y rous asrs rymg ereo n r propor ions 0 0 er mg en s, a

was heated to 200 at a pressure of 80 p.s.1.g. and then commonly used m the soap industry may be included, I spray-dried n a conventional spray-drying tower havlng 1f diam-ed Such perfumes and dyes an enterin air tem erature of 200 F A method of preparing the spray-dried, granulated 10 g p soap product so that it will have non-clotting, irregular and scraggly shaped particles comprises heating an aqueompnems w g ggg ous slurry of the above soap product to a temperature from about 19 F to about ,2150 F at atmosphenc Sodium Soap (92.5%SodiumTa1lowS0apand7.5%Sodium pressure. The/aqueous slurry is then spray-dried at a Cocongt oil Soap) 80.0 pressure from about 80 psig. to about 300 p.s.i.g. and snmmm 3:; at an entering air temperature of about 200 F. in the spray-drying tower. Another method of preparing the 100-0 spray-dried granulated soap product so that it will have I non-clotting, irregular and scraggly shaped particles com- 20 spraydl'led granulated QP pl'oduct conslsted prises heating an aqueous slurry of the above soap prodmlXed 'P and scra'ggly P a had 38 not to a temperature from about 190 F. to about 350 $901? of F. under av pressure of from about 8O p.s.i.g. to about Example 8 M p.s.i.g. then spray drying at an entermg all tem- .Aniaqueous slurry of a 03p product having the folp f 9 b 111 p ytower- The lowing composition by weight on an anhydrous basis was combination of heat and pressure tends to deaerate the h t d g 200 F at a pressure f i d h yfl when the Pressure 13 as when p y spray-dried in a conventional spray-drying tower having through a nozzle much of the water is released by flashan entering i temperaturaof 0 F. ing and the slurry is separated into many scraggly particles. Since a portion of the water is evaporated by 30 Components Percentby flashing, lower than normal tower temperatures can be Weight used, and this will tend to prevent heat puffing and round- I 7 ing of the particles. In either process, however, the Sodium Soap (92.5%Sodium TallowSoapand7.5%Sodium conventional rate of feed of the aqueous slurry and the 9 g conventional amount of air used in atomizing should be Sodium Xylene snl g I 6.7 carefully controlled to produce consistently irregular and To'tL x f i scraggly shaped particles. 1 I

The soap product and process of the invention will be Th I e spray-dried granulated soap product consisted of {gather illustrated In connection with the examples be 40 very lscraggly particles and had a 010m ng of Li Example 5 I v 7 Example l .I I An'aquwP? Slurry of Soap Product having the P :An aqueous slurry of a soap pi'oduct having the folmg COIIIPOSltlOgI by weight on an anhydrous basis was lowing composition by, weight on an anhydrous basis heated at a Ill-assure of 80 i and then was heated to 200 .F. at a pressure of 80 p.s.i.g. and .spray'dned i a.cnvent1na1 sPmy-diymg tower then spray-driedin' a conventional spray-drying tower mg an entering air temperature of 200 F. having an angering temperature of I Components Pe r c e g Ey i n -S wggg v l I 1 v 8' dl mSoap 92.57 Sodium Tallow Soap and 7.5 7 Sodium 0051mm 0580353 fifiifi il isiiffi li?iil fffffiffif??? 88.8 Sodium Carb Sodium Smog v 6.7 Swim Xylene Sflffmafe Sodium Xyl'erie'SulIonate' 4.5

Th spray-.dried granulated soap product consisted. Of The pray-dried granulated. ba od t consisted of Practically all g y Pfl and a clofllng scolfe very scraggly particles and had a clotting score of 1.1.

. Example 6 I 6 Example 10 i g 7. fA njaqueous ,slm'ry, of a soap product having the 01- 9 9- f B product fi g i' lowinglcomposition byweight on an anhydrous basis was owmg iP y h on an an ous o d th was heated to 200 F. at a pressure of 80 p.s.1.g.'and then heated to 200 F. at a pressure of 80 p.s.1.g. an en d 2 I, d h spray-dried in aiconventional spray drying tower having Pmy iq ggz P i avlhng an enteringair temperature of 200 F. an en ermg i b o' r" it Components Pwggty omponen s wgirhty S d S 92.5 Sodum Tallow Soap and7.57 Sodium Sodium Soap (92.57 Sodium Tallow Soap and7.57 Sodium aif i 2-9 s.%?3i8;t a: X5211; Sulfonate 6: 7 Sodium Xylene Sulfnnate 2. 3 t L 100. 0 Total. 100. 0 

1. A SPRAY-DRIED, NON-CLOTTING, GRANULATED SOAP PRODUCT CONSISTING ESSENTIALLY OF FROM ABOUT 6% TO ABOUT 18% OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL CARBONATES AND ALKALI METAL SILICATES, FROM ABOUT 2% TO ABOUT 18% OF AN ALKALI METAL XYLENE SULFONATE, AND FROM ABOUT 64% TO ABOUT 92% OF A MIXTURE OF ALKALI METAL COCONUT OIL SOAP AND ALKALI METAL TALLOW SOAP, SAID MIXTURE OF SOAPS CONSISTING OF FROM ABOUT 1% TO ABOUT 20% OF ALKALI METAL COCONUT OIL SOAP AND FROM ABOUT 99% TO ABOUT 80% OF ALKALI METAL TALLOW SOAP RESPECTIVELY, ALL AMOUNTS BEING BY WEIGHT ON AN ANHYDROUS BASIS THE ALKALI METAL CATION OF ALL OF SAID COMPOUNDS BEING SELECTED FROM NTHE GROUP CONSISTING OF SODIUM AND POTASSIUM. 